Browsing by Author "Dias, V."
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- ENCERRAMENTO PERCUTÂNEO DE COMUNICAÇÃO INTERAURICULAR E FORAMEN OVALE PATENTE EM ADULTOS – A EXPERIÊNCIA DE UM CENTROPublication . Vieira, M.; Dias, V.; Meireles, A.; Gomes, C.; Antunes, N.; Anjo, D.; Guedes, R.; Oliveira, F.; Cabral, S.; Pereira, L.; Braga, P.; Cyrne-Carvalho, H.; Torres, S.
- HOME MONITORING SYSTEM EM DOENTES COM POLINEUROPATIA AMILOIDÓTICA FAMILIARPublication . Vieira, M.; Dias, V.; Meireles, A.; Gomes, C.; Antunes, N.; Anjo, D.; Roque, C.; Reis, H.; Lagarto, V.; Cyrne-Carvalho, H.; Torres, S.
- Non-Transferrin-Bound Iron (NTBI) Uptake by T Lymphocytes: Evidence for the Selective Acquisition of Oligomeric Ferric Citrate SpeciesPublication . Arezes, J.; Costa, M.; Vieira, I.; Dias, V.; Kong, X.; Fernandes, R.; Vos, M.; Carlsson, A.; Rikers, Y.; Porto, G.; Rangel, M.; Hider, R.; Pinto, J.Iron is an essential nutrient in several biological processes such as oxygen transport, DNA replication and erythropoiesis. Plasma iron normally circulates bound to transferrin. In iron overload disorders, however, iron concentrations exceed transferrin binding capacity and iron appears complexed with low molecular weight molecules, known as non-transferrin-bound iron (NTBI). NTBI is responsible for the toxicity associated with iron-overload pathologies but the mechanisms leading to NTBI uptake are not fully understood. Here we show for the first time that T lymphocytes are able to take up and accumulate NTBI in a manner that resembles that of hepatocytes. Moreover, we show that both hepatocytes and T lymphocytes take up the oligomeric Fe3Cit3 preferentially to other iron-citrate species, suggesting the existence of a selective NTBI carrier. These results provide a tool for the identification of the still elusive ferric-citrate cellular carrier and may also open a new pathway towards the design of more efficient iron chelators for the treatment of iron overload disorders.
- Physiological implications of NTBI uptake by T lymphocytesPublication . Pinto, J.; Arezes, J.; Dias, V.; Oliveira, S.; Vieira, I.; Costa, M.; Vos, M.; Carlsson, A.; Rikers, Y.; Rangel, M.; Porto, G.In iron overload disorders a significant fraction of the total iron circulates in the plasma as low molecular weight complexes not bound to transferrin, known as non-transferrin-bound iron (NTBI). By catalyzing the formation of free radicals, NTBI accumulation results in oxidative stress and cellular damage, being a major cause of organ toxicity. NTBI is rapidly and preferentially cleared from circulation by the liver and the myocardium, the main disease targets in iron overload conditions. We have recently demonstrated that human peripheral blood T lymphocytes take up NTBI in vitro, with a pattern that resembles that of hepatocytes. Since T lymphocytes constitute a numerically important component of the circulating cell pool, these findings support a putative role for this cell type in the systemic protection against iron toxicity. Here we tested the hypothesis that the circulating peripheral blood T lymphocyte pool constitutes an important storage compartment for NTBI and is thus a modifier of NTBI deposition in target organs. First we show that NTBI uptake by human T lymphocytes increases the expression of the iron-storage protein ferritin and of the iron exporter ferroportin via an IRE-dependent mechanism. NTBI retention by T lymphocytes is shown to be critically controlled by the hepcidin-mediated modulation of ferroportin both in vitro and in vivo. Finally, the protective effect of T lymphocytes was tested by analyzing the patterns of iron accumulation in the T lymphocyte-deficient mouse model Foxn1(nu) before and after reconstitution with T lymphocytes by adoptive transfer. The results confirmed a significant increase of liver and pancreas iron accumulation in T lymphocyte-deficient mice. NTBI accumulation in the liver and spleen was prevented by reconstitution with syngeneic T lymphocytes. Altogether, our results demonstrate that T lymphocytes are important components of a circulating "NTBI storage compartment" and show its physiological relevance as a modifier of tissue iron overload.
- PROGNÓSTICO A CURTO E LONGO PRAZO E FOLLOW-UP ANGIOGRÁFICO APÓS INTERVENÇÃO CORONÁRIA PERCUTÂNEA COM STENTS REVESTIDOS COM RAPAMICINA EM OCLUSÕES CORONÁRIAS CRÓNICAS: ESTUDO PROSPECTIVO DE UM CENTROPublication . Vieira, M.; Dias, V.; Meireles, A.; Gomes, C.; Antunes, N.; Anjo, D.; Luz, A.; Dias, H.; Correia, A.; Pinto, R.; Silveira, J.; Sousa, P.; Cyrne-Carvalho, H.; Torres, S.
- Successful management of Listeria monocytogenes pericarditis: case report and review of the literature.Publication . Dias, V.; Cabral, S.; Anjo, D.; Vieira, M.; Antunes, N.; Carvalheiras, G.; Gomes, C.; Meireles, A.; Mendonça, T.; Torres, S.Listeria monocytogenes, although an uncommon cause of illness in the general population, is feared principally because of the morbidity and mortality associated with CNS infections. Cardiovascular involvement with L. monocytogenes is very rare, and has been limited to endocarditis. We describe a case of Listeria pericarditis, which occurred in a 60-year-old man with Child-Pugh B cirrhosis who presented to the emergency department with asthenia, anorexia, and respiratory distress. The echocardiogram showed severe pericardial effusion and after pericardiocentesis, L. monocytogenes was isolated in the culture of pericardial fluid. After surgical pericardiectomy with draining of the pericardial effusion and antibiotic treatment with ampicillin, the patient experienced a slow, but full recovery. Documentation of L. monocytogenes pericarditis is an extremely rare entity with very scarce reports in medical literature, and is usually associated with a very poor prognosis. A case report is presented together with a review of the literature.